First of all, radical is a totally relative term. One man's radical is another man's moderate.
Secondly, how can you presume to know who is electable and who is not. I've always thought that I can be a very effective spokesman for my beliefs. Although I have strong convictions, I'm willing to listen to people, answer questions, and address concerns. This makes me more electable than a centrist who's a terrible salesman.
But my main question is this: Why do we have primary elections? Is it to select the candidate with the best chance of winning, or is it to select the candidate who shares our vision for the world? I envision a world in which individual human beings are treated with dignity, where his or her God-given rights will be cherished and protected. Government exists for the protection of the individual human being and the promotion of liberty and order in society. If government interferes with this vision of individual dignity, I say cut the size of government. If individuals threaten the rights and dignity of other individuals, I say increase the size of government. That's my vision. It's not too far right. It's just right.